Detent mechanism for a control valve

ABSTRACT

A control valve includes a main valve spool movable to a plurality of positions. A detent mechanism with a plurality of operational modes operates to releasably hold the main valve spool in displaced positions. An operator-controlled selector mechanism is coupled to the detent mechanism and is operable to selectively place the detent mechanism in a selected one of its operational modes.

BACKGROUND OF THE INVENTION

The present invention relates to a detent mechanism for releasablyholding a spool valve member in selected positions.

Control valves for controlling remote hydraulic functions are wellknown. In some applications, such as for controlling a hydrauliccylinder on a front-end loader, a control valve with no-detent functionis used. Other applications, such as controlling fluid flow to ahydraulic motor, require a control valve which is detent-held in certainpositions. Yet another application, such as controlling fluid flow tocertain hydraulic cylinders, requires a valve with a detent functionwherein the detent is automatically "kicked out" when the cylinderreaches the limit of its travel. Heretofore, these differentapplications have required different control valves. It would bedesirable to have a single valve capable of being selectively placed invarious detent functional modes.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a control valve with adetent function which can be selectively modified by an operatoradjustment.

Another object of the present invention is to provide a control valvewith an operator-adjustable detent mechanism which can be adjustedwithout the use of special tools.

A further object of the present invention is to provide a control valvewith a detent mechanism which can be selectively placed in a no-detentmode and a continuous-detent mode.

A further object is to provide such a control which can be selectivelyplaced in a detent kick-out mode.

These and other objects are achieved by one embodiment of the presentinvention wherein one end of a control valve spool carries outwardlybiased detent balls and is received in a hollow sleeve which may berotated by an operator to a detent position wherein a set ofspaced-apart grooves are positioned to releasably receive the detentballs. The sleeve may also be rotated to a no-detent position whereingrooves which connect extend and retract detent recesses receive thedetent balls so that the valve spool may be freely moved withouthindrance from the detent balls. In another embodiment, the controlvalve spool receives a pressure-operated detent piston which has agroove for receiving the detent balls and a frustoconical surface whichcan engage the detent balls and urge them outwardly for receipt byspaced-apart detent grooves in the sleeve. An operator-controlled detentcontrol valve is adjustable to control the pressure which acts on thedetent piston, thereby providing pressure-operated, operator-selectabledetent and non-detent modes. In a third embodiment, the detent controlvalve includes spring-biased poppet valves and a loadpressure-responsive detent release piston. The spring bias isoperator-adjustable to provide a continuous detent mode, a loadpressure-responsive detent kick-out mode, and a no-detent mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a control valve with anoperator-selectable detent mechanism constructed according to thepresent invention.

FIG. 2 is a cross-sectional view of an alternate embodiment of thepresent invention.

FIG. 3 is an enlarged view of a portion of FIG. 2.

FIG. 4 is an enlarged view similar to FIG. 3, but of another embodimentof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a spool-type hydraulic control valve 10 includes avalve housing 12 with a valve bore 14 extending therein. A valve member16 is slidably received in the bore 14 and cooperates with variousgrooves and lands to control fluid flow to a load 15 such as a cylinderor a motor. A hollow end 18 of the valve member has at least one(preferably three) radially extending detent apertures 20, each of whichreceives a detent ball 22. A cylindrical member 24 is slidably receivedin the hollow end 18. A hollow cylindrical member 25 is slidably mountedon member 24 and includes a frustoconical surface 26 which engages thedetent ball 22. Springs 28 and 30 are biased to urge member 25 to theright, viewing FIG. 1, so that the surface 26 urges the detent ball 22outwardly. Also, load pressure via passage 27 and check valve 29 actsupon member 24 to urge it to the right, viewing FIG. 1.

The springs 28 and 30 are not strong enough by themselves (without loadpressure) to maintain the detent balls 22 in their detent position.Thus, when pump (and load) pressure is lost, the members 24 and 25 willmove to the left and allow the detent balls 22 to retract, thus allowingthe main valve member 16 to freely return to its neutral position underthe influence of centering spring 64. This gives the control valve 10 a"neutral start" capability. Plug 63 limits the travel of member 24 sothat the spring 30 does not go solid. This allows the operator tomanually pull valve member 16 out of one of its detented positions. Thecheck ball 29 is located between pressure passage 27 and member 24 toprevent premature disengagement from a detented position due to amomentary pressure drop in passage 27.

A hollow cylindrical detent cap 32 includes a base 34 sealingly androtatably received in the axially outer portion of the bore 14 andextends axially outwardly from the housing 12. The cap 32 slidably andsealingly receives the hollow end 18 of the valve member. One portion ofthe inner surface of cap 32 includes a plurality of spaced-apart detentrecesses 36, 38 and 40 for receiving the detent ball 22 and therebyreleasably holding the valve member 16 in a corresponding plurality ofpositions. The inner surface of cap 32 also includes three continuousaxially extending recesses 42 which have a length which is substantiallyequal to the distance between opposite sides of recesses 36 and 38, eachof which is capable of receiving a corresponding one of the detent balls22.

A selector knob 50 is fixed to the cap 32 so that manual rotation ofknob 50 causes rotation of cap 32 about its central axis. In thismanner, the knob 50 is rotated to rotate cap 32 from the first positionshown wherein the detent recesses 36, 38 and 40 will releasably hold thevalve member in a plurality of spaced-apart axial positions to a secondposition wherein recess 42 will receive ball 22 so that the valve member16 will be freely movable axially over a distance equal to slightly lessthan the axial length of groove 42.

The knob 50 includes one side 52 which faces and is adjacent to an end54 of the valve housing 12. A blind bore 56 extends part way into side52 and receives a detent ball 58 and a detent spring 60. The housing end54 includes a recess 62 which receives ball 58 to releasably hold knob50 in the position shown and a second recess (not shown) which receivesthe ball 58 to releasably hold the knob 50 in a (no detent) positionwherein the balls 22 will be received by the long recess 42.

An alternate embodiment is shown in FIGS. 2 and 3 wherein the controlvalve 110 includes a valve housing 112 with a main valve bore 114extending therein for slidably receiving main spool valve member 116. Ahollow end 118 of spool 116 receives a detent piston 120 and cooperatestherewith to form a detent control chamber 122. A plurality of radialopenings 124 receive detent balls 126 which are received by detentrecesses 128 and 130 in detent sleeve 132. Another set of detent balls125 are received in apertures 127 in sleeve 132 and are biased by spring129 and spring slider 131 for engaging shoulder 133 to releasably holdthe main spool 116 in a float position. Chamber 122 is communicated withbore 114 via radial ports 123.

The detent piston 120 includes a piston member 134 from which extends ashaft 136 on which is slidably mounted a head 138. The head 138 has anannular peripheral groove 140 therein, one end of which defines afrustoconical surface 142. A spring 144 is coupled between piston member134 and head 138 and spring 146 is coupled between head 138 and capmember 148 which is threadably coupled to the hollow end 118. Cap member148 is coupled to valve centering spring 150 via spring guides 152 and154, all contained within a closure cap 156.

A second valve bore 160 extends into the valve housing 112 and receivesa detent valve assembly 162. The inner end of bore 160 is communicatedto load pressure via passage 164 and to control chamber 122 via passage165 and ports 123. The detent valve assembly includes a detent valvesleeve 166 which is sealingly received in an enlarged portion of bore160 and is held in place by a threaded connection at 168. A poppet valvebore 170 extends axially through sleeve 166 and includes a reduceddiameter portion forming a poppet valve seat 172. Radial port 171communicates bore 170 with a groove 173 which is connected to sump via apassage which is not shown. A poppet valve member 174 is received withinbore 170 and includes a conical seat portion 175 for sealingly engagingseat 172, a base 176 and a stem 178. Spring 180 is biased to urge poppetvalve member 178 into engagement with seat 172. A similar poppet valvemember is described in U.S. Pat. No. 4,303,098, issued 1 Dec. 1981,which is incorporated by reference herein.

An operator-movable control knob 182 is connected to a shaft 184 whichis threadably received by sleeve 166 and the end which engages the step178 of poppet valve 174. In the position shown in FIG. 3, the shaft 184is holding poppet valve member 174 slightly away from seat 172 so thatdetent control chamber 122 will be communicated with sump via port 123,passage 165, bore 170 and groove 173. With sump pressure in controlchamber 122, the detent piston 120 is in position to allow the detentballs to retract radially into grooves 140 and the spool valve 116 canbe moved without any detent function. If the control knob is turnedcounterclockwise, the shaft 184 will be withdrawn from bore 170 allowingpoppet valve member 174 to engage seat 172 which blocks thecommunication between control chamber 122 and sump. Load pressure iscommunicated to chamber 122 via passages 164, 665 and ports 123, thusurging detent piston to the right, viewing FIG. 3. The frustoconicalsurface 142 urges the detent balls 126 radially outwardly so that whenthe spool 116 is moved left or right, the detent balls will enterrecesses 128 or 130 to releasably hold the spool 116 in its displacedposition. A screw 185 has an end which is engageable with detent piston120 to prevent spring 144 from being completely compressed. This allowsan operator to pull the main valve member 116 out of its detent-heldpositions. As in the previous embodiment, hydraulic pressure is requiredso that head 138 will bias the detent balls 126 outwardly and hold themain valve member 116 in a detent-held position. When pump pressure islost, the pressure in chamber 122 drops to permit head 138 to move tothe left, thus releasing the main valve member from a detent-heldposition and allowing it to automatically return to a neutral position.

Another alternate embodiment is shown in FIG. 4. Portions of thisembodiment are similar to parts of the embodiment of FIGS. 2 and 3 andcommon reference numerals are assigned to such parts. The FIG. 4embodiment differs from the FIG. 2 and 3 embodiment with respect to thedetent control valve 200. A valve bore 202 extends into housing 112 andcommunicates with passages 164 and 165. A passage symbolically indicatedby line 204 communicates a large diameter portion 206 of bore 202 withsump pressure.

A poppet seat member 208 is threadably held in place in bore 202 betweenpassages 165 and the large diameter portion 206. A central bore 210extends through member 208 and forms poppet seat 212. A plurality ofprojections or ridges 213 extend axially and radially from the end ofpoppet seat member 208 which faces towards passage 164 and which isexposed to fluid pressure in passage 165. Poppet valve member 174(identical to that shown in FIG. 3) is partially received in bore 210and its seat 175 is sealingly engageable with poppet seat 212.

A kick-out spool 220 is slidably and sealingly mounted in bore 202between passage 164 and poppet seat member 208. A blind central bore 222extends into spool 220 and a pair of radial ports 224 and 226communicate bore 222 to the exterior spool 220. The stem of poppet valvemember 174 engages the end of kick-out spool 220. The base of poppetvalve member engages a spring seat 230 which is received and retainedwithin kick-out sleeve 232 and which is biased into engagement withpoppet valve member 174 by spring 234. Kick-out sleeve 232 is threadablycoupled to a shaft 236 which is coupled for rotation with manuallyrotatable control knob 238. The kick-out sleeve 232 is non-rotatablymounted in the large diameter bore portion 206. This can be accomplishedby giving periphery of kick-out sleeve 232 and the bore portion 206 ahexagonal or polygon-shape, thus forcing sleeve 232 to move axiallywithin bore portion 206 as shaft 236 is rotated. Alternatively, key andslot arrangements could also be used.

The embodiment of FIG. 4 has three different functional modes--ano-detent mode, a continuous-detent mode and a detent kick-out mode.

The no-detent mode would be used when the control valve is connected tooperate the hydraulic cylinder of a loader. The continuous-detent modewould be used if the control valve is connected to operate abi-directional hydraulic motor (not shown). The detent kick-out modewould be used when the control valve is connected to operate thehydraulic cylinder of an agricultural implement (not shown).

The no-detent mode is illustrated in FIG. 4 because the poppet valvemember 174 is spaced away from seat 212. This allows sump pressure to becommunicated to detent control chamber 122 via bore 210, between ridges213 and via passage 165 and ports 123. As was the case with the FIG. 2embodiment, this allows detent balls to retract into groove 140 ofdetent piston 120, and the main spool 116 can then be moved withoutbeing detent held by detent balls 126.

The continuous detent mode is achieved by turning the control knob 238clockwise which moves sleeve 232 and spring seat 230 to the left,viewing FIG. 4. This moves the poppet valve 174 into tight sealingengagement with poppet seat 212, thus blocking communication betweendetent control chamber 122 and sump. Load pressure from passage 164 iscommunicated via bore 222, port 226, passage 165 and ports 123 to detentcontrol chamber 122 so that piston 120 will urge detent balls 126radially outwardly for reception into detent recesses 128 and 130.

The detent kick-out mode is achieved by reducing the compression load inspring 234. The detent kick-out mode operates as follows. Assuming thatthe spool 116 is initially in a detent-held position such that thecylinder 15 is being extended, first, the control knob 238 is rotatedcounterclockwise from the continuous detent position to reduce thecompression load of spring 234.

Then, when the load pressure 164 becomes high enough, such as when thecylinder 15 is fully extended, this load pressure will overcome thereduced force of spring 234 and move poppet valve member 174 to theright and the kick-out spool 220 will move to the right due to pressuredrop since 174 opens to sump. Port 224 continues to move into bore 220which shuts off pressure oil to 122. Since the poppet valve 174continues to bleed pressure oil to sump, the detent piston 120 moves tothe left and detent balls 126 will release.

As in the previous embodiments, hydraulic pressure is required to engagethe detent balls into grooves 128 and 130, and when pump pressure isshut off, the detent mechanism disengages so that the spool 116automatically returns to its neutral position. In certain applications,it is desirable not to have the detent kick-out or neutral startfunctions operate from the float position of the main valve member 116.The embodiment of FIGS. 2 and 3 shows this type of float detent whereindetent balls 125 are spring-biased by spring 129.

While the invention has been described in conjunction with a specificembodiment, it is to be understood that many alternatives, modificationsand variations will be apparent to those skilled in the art in light ofthe aforegoing description. Accordingly, this invention is intended toembrace all such alternatives, modifications and variations which fallwithin the spirit and scope of the appended claims.

I claim:
 1. A detent mechanism for a valve controlling fluidcommunication between a sump, a pressure source and a hydraulicfunction, the valve having a housing defining a valve bore therein and amain valve member movable in the bore to control fluid flow, the detentmechanism comprising:a control chamber; a detent means for moving to afirst position releasably holding the main valve member in a pluralityof spaced apart positions, and for moving to a second position andpermitting the main valve member to freely move between said spacedapart positions, the detent means being movable in response to fluidpressure in the control chamber; an operator-controlled valve forcontrolling fluid pressure in the control chamber, theoperator-controlled valve comprising a housing having a valve boretherein, a first passage communicating the valve bore with a fluidpressure source, a second passage communicating the valve bore with asump and a third passage communicating the valve bore with the controlchamber, the operator-controlled valve also comprising anoperator-controlled control valve member being movable in the valve boreto control communication between the first, second and third passages,the control value member being movable to a detent position whereincommunication between the first and third passage is open andcommunication between the second and third passages is closed and to anon-detent position wherein communication between the second and thirdpassages is open; a resilient member coupled to the control valve memberand biased to urge the control valve member to its detent position; apressure-responsive member exposed to fluid pressure from the fluidpressure source, the pressure-responsive member engaging the controlvalve member and moving the control valve member from its detentposition to its non-detent position when the pressure of the fluidpressure source overcomes the bias of the resilient member; andoperator-controlled means for adjusting the bias of the resilientmember.
 2. A detent mechanism for a valve controlling fluidcommunication between a sump-a pressure source and a hydraulic function,the valve having a housing defining a valve bore therein and a mainvalve member movable in the bore to control fluid flow, the detentmechanism comprising:a detent means for moving to a first detentposition and releasably holding the main valve member in a plurality ofspaced apart positions, and for moving to a second non-detent positionand permitting the main valve member to freely move between said spacedapart positions; an operator-controlled selector means coupled to thedetent means for selectively maintaining the detent means in either ofits first and second positions; a pressure-responsive member exposed tofluid communication to the hydraulic function and movable in response tochanges therein; and means for operatively coupling thepressure-responsive member to the selector means, thepressure-responsive member and the selector means cooperating to movethe detent means from its first detent position to its second non-detentposition when the fluid pressure communicated to the hydraulic functionexceeds a predetermined level.
 3. A detent mechanism for a valvecontrolling fluid communication between a sump, a pressure source and ahydraulic function, the valve having a housing defining a valve boretherein and a main valve member movable in the bore to control fluidflow, the detent mechanism comprising:a detent element having aplurality of spaced-apart detent recesses therein; an aperture extendingradially through a detent portion of the main valve member; a detentball received in the aperture for radial movement therein and releasablyreceivable by the detent recesses; a detent member engageable with thedetent ball, received by the detent portion of the main valve member andmovable therein to a first position urging the detent ball into the oneof the detent recesses and to a second position permitting the detentball to move out of the detent recesses, the detent member comprising ahead member having a groove therein for receiving the detent ball and aramp for engaging the detent ball and urging the ball out of theaperture and towards the detent element, and a piston member coupled tothe head member and exposed to fluid pressure in a detent controlchamber, the piston and head members being movable in response to fluidpressure changes in the detent control chamber; and a detent controlvalve means for controlling the fluid pressure in the detent controlchamber.
 4. The detent mechanism of claim 3, wherein:one of the head andpiston members has a shaft projecting therefrom, the other of the headand piston member having a bore therein which slidably receives theshaft; and a resilient member is coupled between the piston member andthe head member and is biased to urge the head member and its ramptoward the detent ball.
 5. The detent mechanism of claim 3, wherein:thedetent portion of the main valve member is hollow; and the detent memberis received within the detent portion.
 6. The detent mechanism of claim3, wherein:the detent member and the main valve member enclose thedetent control chamber; and a detent control passage extends through themain valve member and forms a portion of a passage which communicatesfluid pressure from the detent control valve to the detent controlchamber.
 7. A detent mechanism for a valve controlling fluidcommunication between a sump, a pressure source and a hydraulicfunction, the valve having a housing defining a valve bore therein and amain valve member movable in the bore to control fluid flow, the detentmechanism comprising:a detent element having a plurality of spaced-apartdetent recesses therein, the detent element comprising a hollow sleevewhich receives a detent portion of the main valve member, the detentportion of the main valve member having annular shoulder thereon, thedetent recesses being formed by annular grooves on an inner surface ofthe hollow sleeve, the detent element including an opening extendingradially therethrough; an aperture extending radially through the detentportion of the main valve member; a detent ball received in the aperturefor radial movement therein and releasably receivable by the detentrecesses; a detent member engageable with the detent ball, received bythe detent portion of the main valve member and movable therein to afirst position urging the detent ball into the one of the detentrecesses and to a second position permitting the detent ball to move outof the detent recesses; a further detent ball received in said openingfor radial movement therein; and means for releasably urging the furtherdetent ball radially inwardly for engagement with the shoulder andreleasably holding the main valve member in a further position.